The present invention relates generally to ultrawideband communication systems and more particularly to packet synchronization for ultrawide band communication systems.
Digital communication using an ultrawideband (UWB) system can provide for robust communication. Utilization of a wide band of frequencies may allow high rate communication between devices to occur, often without interfering with other services. Orthogonal frequency division multiplexing (OFDM), which divides a frequency band into multiple smaller frequency bins, may advantageously spread communication over the frequency band of a UWB system. UWB systems may additionally utilize frequency hopping to further spread communication over an available frequency spectrum.
Data communication in a UWB system is often divided into packets. Generally, the beginnings of packets are marked with preamble sequences. Preamble sequences often are useful in that they may allow receivers to determine the presence of a packet and prepare to process data of a packet, among other reasons. For efficient utilization of available data bandwidth, packet preambles generally should be short so that the overhead of their transmission is low. However, reliable detection of packets is also desired, for example to avoid packet loss and subsequent loss of data bandwidth to retransmission. The ability to detect a packet of a given size generally depends on the choice of preamble sequence.
In addition, preferably a preamble sequence provides information allowing a receiver to not only determine that a packet is present, but where data information may be found in a packet. Unfortunately, it may be difficult to determine both that a packet is present and when to begin processing data of a packet based on a preamble sequence.